The idea that children will grow up to be better off than their parents is a central component of the American Dream, and sustains American optimism. However, Downward Mobility from the Middle Class: Waking up from the American Dream finds that a middle-class upbringing does not guarantee the same status over the course of a lifetime.  A third of Americans raised in the middle class—defined here as those between the 30th and 70th percentiles of the income distribution—fall out of the middle as adults. The data also show differences in rates of downward mobility from the middle based on both family background and personal characteristics.  See report from the Economic Mobility Project of the Pew Charitable Trusts here.